Work flow of jitsi videobridge code

I am checking jitsi videobridge code and have a question about how rtp packet is transferred from one user to another. For example, videobridge create rtpchannels for one user and send/receive rtp/rtcp packet with in/out streams in this channel. but I do not know how a rtp packet received in a channel to be sent to other channels(users) in the same conference. could you help on this? thanks in advance.